Particle stabilized foam, and slurries, product, and methods related thereto

Abstract

Disclosed are cementitious product, as well as cementitious slurry, and method of forming the product. To reduce density in the cementitious product, foam is included in the slurry and in the method of forming the product. The slurry includes cementitious particles, water, and air bubbles such as from compressed air. Instead of using detergent chemistry at the gas/water interface of bubbles, the present invention uses a surface modifying agent for the cementitious particles in the slurry. The modified particles act to produce stable foam in the slurry. As an example mode of introduction, the surface modifier can be added (e.g., as solid or solution) directly into a bulk cementitious slurry that forms the product. As another example, the surface modifier can be added in a separate solution with water, air bubbles, and cementitious particles that serve as additive to the main cementitious slurry, where the separate solution is then added to the main cementitious slurry.

The invention claimed is: 
     
       1. A foamed slurry for forming a product, the slurry comprising:
 (a) water; 
 (b) cementitious particles, wherein the cementitious particles comprise stucco, calcium sulfate dihydrate, coated calcium sulfate dihydrate, or combinations thereof; 
 (c) air bubbles with walls formed by the water; and 
 (d) surface modifying agent effective to modify a surface of at least some of the cementitious particles, such that the modified particles stabilize the air bubbles sufficiently to form air voids in the product, 
 wherein the surface modifying agent comprises one or more gallate compound of Formula I: 
 
       
         
           
           
               
               
           
         
       
       wherein R is selected from the group consisting of C 1 -C 10  alkyl, C 1 -C 10  alkenyl, C 1 -C 10  alkynyl, C 3 -C 12  cycloalkyl, C 3 -C 12  cycloalkenyl, or C 6 -C 10  aryl, wherein the alkyl, alkenyl, and alkynyl groups are branched or unbranched, and optionally substituted with one or more substituents selected from the group consisting of halo, alkoxy, ester, or substituted amide, 
       wherein the foamed slurry has a pH of about 7.5 to about 9. 
     
     
       2. The foamed slurry of  claim 1 , wherein the slurry comprises about 0.015 wt. % or less of detergent surfactant. 
     
     
       3. The foamed slurry of  claim 1 , wherein R is characterized as C 1 -C 6  alkyl, C 1 -C 6  alkenyl, C 1 -C 6  alkynyl, C 3 -C 8  cycloalkyl, C 3 -C 8  cycloalkenyl, C 6 -C 8  aryl, wherein the alkyl, alkenyl, and alkynyl groups are branched or unbranched, and optionally substituted with one or more substituents selected from the group consisting of halo, alkoxy, ester, or substituted amide. 
     
     
       4. The foamed slurry of  claim 1 , wherein R is C 1 -C 6  alkyl. 
     
     
       5. The foamed slurry of  claim 1 , wherein the surface modifying agent is propyl gallate. 
     
     
       6. The foamed slurry of  claim 1 , wherein the surface modifying agent is present in an amount from about 0.1% to about 7% by weight of the cementitious particles. 
     
     
       7. The foamed slurry of  claim 1 , further comprising starch in an amount from about 0.1% to about 10% by weight of the cementitious particles. 
     
     
       8. The foamed slurry of  claim 1 , wherein the slurry further comprises starch.